The main vascular landmark in close association with the right main stem bronchus is the right pulmonary artery.

Ascending aorta

Superior vena cava

The latter courses almost horizontal first anterior to the ascending aorta and the superior vena cava, and then anterior to the right main stem bronchus.

The pulmonary artery is in close contact with the airway at the take-off of the right upper lobe bronchus where it divides into two branches ; the main right upper lobe artery, and the posterior ascending artery.

Pulmonary vein

The pulmonary vein is located slightly below the artery. Two main branches returning blood from the upper lobe join the middle lobe veins to form the upper pulmonary vein. These vessels are not in direct contact with the bronchus.